Thread Problem on application exit

[lyar1031]

I have a single threaded applicaation and I am getting a error CANNOT ACCESS A DISPOSED OBJECT when I exit the application (Hitting the X on the top right hand corner of the Dialog Box).


Here is where the error is occurring! I will Show the code snipet

private void ThreadFunc()
{/* Thread Func */

/* Get current Thread Running */
Thread Current = Thread.CurrentThread;

while (!ThreadStop)
{
if (Current.IsAlive == true)
{
SharedLocation.GetData = SharedLocation.GetData + 1;
DisplayData(SharedLocation.GetData);
SetSelectListBox(SharedLocation.GetData);
Thread.Sleep(Constants.GetSleepTime);

}
}
}

By setting a Flag the thread will exit, which I do in OnFormClosing(Not the correct event name in C#) and I have a Stop Thread Button where I set the flag to stop the thread.

When I stop the thread using my button, then exit the application I get no error. However, when I just exit the Thread w/o pressing the button is where I get the error. Here is the code snipet for the application exiting and the stop thread button being pressed. They both do the same thing.

private void StopThread_Click(object sender, EventArgs e)
{//Button Stop Thread
ThreadStop = true;
SerialPort.Close();
}

private void SerialComm_FormClosed(object sender, FormClosedEventArgs e)
{//Form Closed
ThreadStop = true;
SerialPort.Close();
}

The error occurs in these functions in the thread fucntion at these lines
1. this.Invoke(d, new object[] { Index });
2. this.Invoke(d, new object[] { Data });

in methods

1. DisplayData(SharedLocation.GetData);
2. SetSelectListBox(SharedLocation.GetData)

Here is the code for these 2 functions!

private void SetSelectListBox(int Index)
{/* Select List Box Item From Thread */

// Thread Safe calls to Windows Controls!!
if (this.OutputListBox.InvokeRequired)
{
SetSelectCallback d = new SetSelectCallback(SetSelectListBox);
this.Invoke(d, new object[] { Index });
}
else
{
this.OutputListBox.SelectedItem = Index;
}
}

private void DisplayData(int Data)
{/* Display Data in List Box From Thread */
// Thread Safe calls to Windows Controls!!
// If the calling thread is different from the thread that
// created the control, this method creates a
// SetDataCallback and calls itself asynchronously using the
// Invoke method.
//
// If the calling thread is the same as the thread that created
// the control, then the Control/Set property is set directly.

// InvokeRequired required compares the thread ID of the
// calling thread to the thread ID of the creating thread.
// If these threads are different, it returns true.

if (this.OutputListBox.InvokeRequired)
{
SetDataCallback d = new SetDataCallback(DisplayData);
this.Invoke(d, new object[] { Data });
}
else
{
this.OutputListBox.Items.Add(Data);
}
}

Thanks. The reason for the 2 functions is that I was modifying a control from within my thread and I had read a post that I had to do it this way.

Thanks your help on this is greatly appreciated since I am stuck on this one!!

[darwen]

Instead of just setting a flag for the thread to exit, you need to wait until the thread has exited.

You can either use the Join method in the Thread class to do this, or use an event (usually a ManualResetEvent) which is set after your thread has shut everything down and just before it exits its thread function.

You can use the WaitOne() method on ManualResetEvent to wait until the thread finishes in this instance.

I've written about this many times in this forum - you should be able to do a search and find my responses which are relevant to you.

Darwen.

[lyar1031]

Thanks, I actually chaned it and I just do a mythread.abort();

[darwen]

Abort is the incorrect way of doing it. Your thread should always exit normally : not be forced to.

Darwen.